Develop Reference

cursor blinking changed till restart

I am working on a .net windows forms control where i have used the below code to use modify the caret in my custom textbox
[DllImport("User32.dll")]
static extern bool CreateCaret(IntPtr hWnd, IntPtr hBitmap, int nWidth, int nHeight);
[DllImport("User32.dll")]
static extern bool SetCaretPos(int x, int y);
[DllImport("User32.dll")]
static extern bool DestroyCaret();
[DllImport("User32.dll")]
static extern bool ShowCaret(IntPtr hWnd);
[DllImport("User32.dll")]
static extern bool HideCaret(IntPtr hWnd);
[DllImport("user32.dll")]
static extern bool SetCaretBlinkTime(uint uMSeconds);
protected override void OnGotFocus(System.EventArgs e)
{
CreateCaret(this.Handle, IntPtr.Zero, 8, 14);
SetCaretPos(2, 1);
ShowCaret(this.Handle);
SetCaretBlinkTime(100);
base.OnGotFocus(e);
}
protected override void OnLostFocus(EventArgs e)
{
DestroyCaret();
base.OnLostFocus(e);
}
but i found out that once i run the project , the blinking rate of my windows cursor have changed too till i restart my windows xp (sp2) .
any suggestion on why it is happening ?

To draw a caret by your self:
public class CueTextBox : TextBox
{
[DllImport("User32.dll")]
static extern bool GetCaretPos(out POINT pt);
[StructLayout(LayoutKind.Sequential)]
public struct POINT
{
public UInt32 x;
public UInt32 y;
};
[DllImport("User32.dll")]
static extern bool DestroyCaret();
[DllImport("User32.dll")]
static extern bool HideCaret(IntPtr hWnd);
[DllImport("user32.dll")]
static extern uint GetCaretBlinkTime();
[DllImport("User32.dll")]
static extern bool SetTimer(IntPtr hWnd, IntPtr nIDEvent, uint uElapse, IntPtr lpTimerFunc);
[DllImport("User32.dll")]
static extern bool KillTimer(IntPtr hWnd, IntPtr nIDEvent);
[DllImport("User32.dll")]
static extern bool InvalidateRect(IntPtr hWnd, IntPtr lpRect, Int32 bErase);
private bool show = true;
protected override void OnGotFocus(System.EventArgs e)
{
HideCaret(this.Handle);
IntPtr nIDEvent = new IntPtr(1);
SetTimer(this.Handle, nIDEvent, 100, IntPtr.Zero);
base.OnGotFocus(e);
}
protected override void OnLostFocus(EventArgs e)
{
//SetCaretBlinkTime(530);
IntPtr nIDEvent = new IntPtr(1);
KillTimer(this.Handle, nIDEvent);
show = false;
base.OnLostFocus(e);
}
protected virtual void OnTimer(EventArgs e)
{
InvalidateRect(this.Handle, IntPtr.Zero, 0);
show = !show;
}
protected override void OnPaint(PaintEventArgs e)
{
base.OnPaint(e);
POINT pt = new POINT();
GetCaretPos(out pt);
SolidBrush brush;
if (show)
{
brush = new SolidBrush(Color.Black);
e.Graphics.FillRectangle(brush, pt.x, pt.y, 8, 14);
}
}
const int WM_PAINT = 0x000F;
const int WM_SETFOCUS = 0x0007;
const int WM_KILLFOCUS = 0x0008;
const int WM_TIMER = 0x0113;
protected override void WndProc(ref Message m)
{
base.WndProc(ref m);
if (m.Msg == WM_PAINT)
{
this.OnPaint(new PaintEventArgs(Graphics.FromHwnd(m.HWnd), this.ClientRectangle));
}
if (m.Msg == WM_SETFOCUS)
{
this.OnGotFocus(new EventArgs());
}
if (m.Msg == WM_KILLFOCUS)
{
this.OnLostFocus(new EventArgs());
}
if (m.Msg == WM_TIMER)
{
this.OnTimer(new EventArgs());
}
}
}
Use SetTimer to set a "blinktime", and then InvalidateRect in the WM_TIMER to trigger WM_PAINT message, then simulate the blinking caret in OnPaint method.

moveable form without title

I was looking on this forum earlier to help with this issue i am having. Basically I am dynamically creating a form from a class which i want to be draggable around the screen without the title bars. The code i came across is :
public const int WM_NCLBUTTONDOWN = 0xA1;
public const int HT_CAPTION = 0x2;
[System.Runtime.InteropServices.DllImport("user32.dll")]
public static extern int SendMessage(IntPtr hWnd, int Msg, int wParam, int lParam);
[System.Runtime.InteropServices.DllImport("user32.dll")]
public static extern bool ReleaseCapture();
private void window_MouseDown(object sender, System.Windows.Forms.MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
ReleaseCapture();
SendMessage(Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0);
}
}
However when i try to compile I get the following error:
Error 1 The name 'Handle' does not exist in the current
context C:\Users\xxxxxx\Documents\Visual Studio
2013\Projects\practiceProgressBar2\practiceProgressBar2\Notifications.cs 109 29 practiceProgressBar2
Does anyone know what I am doing wrong as I have been tackling this all day

Change:
SendMessage(Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0);
To:
SendMessage(((Form)sender).Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0);
If you have other controls, like Labels, pointing to that same handler, then you could use this instead to make it drag when you also drag the Labels:
SendMessage(((Control)sender).FindForm().Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0);

Try overriding the form's WndProc method instead.
public const int HTCAPTION = 0x2;
public const int WM_NCHITTEST = 0x84;
public const int HTCLIENT = 1;
protected override void WndProc(ref Message m)
{
base.WndProc(ref m);
if (m.Msg == WM_NCHITTEST)
{
if (m.Result.ToInt32() == HTCLIENT)
m.Result = (IntPtr)HTCAPTION;
}
}

Move windows form from a picturebox in C#

I have a windows form without any border.
So i added a picture box and i want the whole form to be moved when that picture box is clicked.
public const int WM_NCLBUTTONDOWN = 0xA1;
public const int HT_CAPTION = 0x2;
[DllImportAttribute("user32.dll")]
public static extern int SendMessage(IntPtr hWnd,
int Msg, int wParam, int lParam);
[DllImportAttribute("user32.dll")]
public static extern bool ReleaseCapture();
private void header_image_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
ReleaseCapture();
SendMessage(Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0);
}
}
That is the code which i am using atm.But my problem is that if i move cursor very fast it is not sticked on the picture box.
I tried to find a solution but nothing came up.
I used some info from those 2 links:
link 1
link 2
Any ideas?
EDIT:
Here is the whole code of my form
public Form1()
{
InitializeComponent();
}
public const int WM_NCLBUTTONDOWN = 0xA1;
public const int HT_CAPTION = 0x2;
[DllImportAttribute("user32.dll")]
public static extern int SendMessage(IntPtr hWnd,
int Msg, int wParam, int lParam);
[DllImportAttribute("user32.dll")]
public static extern bool ReleaseCapture();
private void header_image_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
ReleaseCapture();
SendMessage(Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0);
}
}

Refer this code:
private bool draging = false;
private Point pointClicked;
private void pictureBox1_MouseMove(object sender, MouseEventArgs e)
{
if (draging)
{
Point pointMoveTo;
pointMoveTo = this.PointToScreen(new Point(e.X, e.Y));
pointMoveTo.Offset(-pointClicked.X, -pointClicked.Y);
this.Location = pointMoveTo;
}
}
private void pictureBox1_MouseDown(object sender, MouseEventArgs e)
{
if (e.Button == MouseButtons.Left)
{
draging = true;
pointClicked = new Point(e.X, e.Y);
}
else
{
draging = false;
}
}
private void pictureBox1_MouseUp(object sender, MouseEventArgs e)
{
draging = false;
}

Use the MouseMove() event instead of MouseDown():
private void header_image_MouseMove(object sender, MouseEventArgs e)
{
if (e.Button == System.Windows.Forms.MouseButtons.Left)
{
ReleaseCapture();
SendMessage(this.Handle, WM_NCLBUTTONDOWN, HT_CAPTION, 0);
}
}

How to detect a keybd_event without focus

I'm working on a program, who need to detect when the user press the keyboard or use his mouse, even if the program is minimized or not focused.
I think I have to use the windows API, keybd_event (user32), but I don't know how to use the "listener" of this event. I have something like that:
[DllImport("user32.dll")]
static extern void keybd_event(byte bVk, byte bScan, uint dwFlags,UIntPtr dwExtraInfo);
void PressKey(byte keyCode)
{
//My code here
}
I did some research, but it's the first time I have to use DllImport, so I don't know how to continue ...
Thanks
(Ps:Sorry about my bad English, this is not my native language :) )
(PPs: I've read all of your answers, but it takes a while to read every link, so I'll work on it tonight, but I think I will find the answer. Anyway, thanks for the links everybody ;) )
Edit: So I just finished my code and it's work :) It looks something like:
[DllImport("user32.dll")]
public static extern Boolean GetLastInputInfo(ref tagLASTINPUTINFO plii);
public struct tagLASTINPUTINFO
{
public uint cbSize;
public Int32 dwTime;
}
private void timerTemps_Inactif_Tick(object sender, EventArgs e)
{
tagLASTINPUTINFO LastInput = new tagLASTINPUTINFO();
Int32 IdleTime;
LastInput.cbSize = (uint)Marshal.SizeOf(LastInput);
LastInput.dwTime = 0;
if (GetLastInputInfo(ref LastInput))
{
IdleTime = System.Environment.TickCount - LastInput.dwTime;
if (IdleTime > 10000)
{
//My code here
}
}
}
Thanks for the help guys ;)

You will need to hook into Windows OS with SetWindowsHookEx function. You should read the article Keyloggers: How they work and how to detect them posted by SecureList to get a understanding ofthe process.

I have always got a good performance by using RegisterHotKey/UnregisterHotKey functions. Sample code:
[DllImport("User32")]
public static extern bool RegisterHotKey(
IntPtr hWnd,
int id,
int fsModifiers,
int vk
);
[DllImport("User32")]
public static extern bool UnregisterHotKey(
IntPtr hWnd,
int id
);
public const int MOD_SHIFT = 0x4;
public const int MOD_CONTROL = 0x2;
public const int MOD_ALT = 0x1;
public const int WM_HOTKEY = 0x312;
protected override void WndProc(ref Message m)
{
if (m.Msg == WM_HOTKEY && m.WParam == (IntPtr)0)
{
IntPtr lParamCTRLA = (IntPtr)4259842;
IntPtr lParamB = (IntPtr)4325376;
if (m.LParam == lParamCTRLA)
{
MessageBox.Show("CTRL+A was pressed");
}
else if (m.LParam == lParamB)
{
MessageBox.Show("B was pressed");
}
}
base.WndProc(ref m);
}
private void Form1_Load(object sender, EventArgs e)
{
this.FormClosing += new FormClosingEventHandler(Form1_FormClosing);
RegisterHotKey(this.Handle, 0, MOD_CONTROL, (int)Keys.A);
RegisterHotKey(this.Handle, 0, 0, (int)Keys.B);
}
private void Form1_FormClosing(Object sender, FormClosingEventArgs e)
{
UnregisterHotKey(this.Handle, 0);
}
You can "register" as many keys (or combination of keys) as you want by emulating the shown structure. All the registered keys will get inside the condition if (m.Msg == WM_HOTKEY && m.WParam == (IntPtr)0); if they are pressed at all (independently upon the program currently being selected). The easiest way to know the specific key/combination being pressed is relying on m.LParam (I got the two values I am including after a quick test with the given keys). You can do a quick research to find out a list of LParam or further constant modifiers (wheel of the mouse, for example).

The final code:
[DllImport("user32.dll")]
public static extern Boolean GetLastInputInfo(ref tagLASTINPUTINFO plii);
public struct tagLASTINPUTINFO
{
public uint cbSize;
public Int32 dwTime;
}
private void timerTemps_Inactif_Tick(object sender, EventArgs e)
{
tagLASTINPUTINFO LastInput = new tagLASTINPUTINFO();
Int32 IdleTime;
LastInput.cbSize = (uint)Marshal.SizeOf(LastInput);
LastInput.dwTime = 0;
if (GetLastInputInfo(ref LastInput))
{
IdleTime = System.Environment.TickCount - LastInput.dwTime;
if (IdleTime > 10000)
{
//My code here
}
}
}

Background keyboard shortcuts that do not propagate to windows

I made an application that needs to handle specific keyboard presses even when the window is not active, now I have this and it works great; however the handled keys are still being propagated to windows (not sure if my app is handling them first, so I may be backwards about that).
Is there any way to have it so my app can handle the key presses I want but not have the keys be sent to the current application/windows.
EX) I have my app open in the background monitoring the number pad for presses, every time I press a number key on the number pad I want to add that number to a text box for display purposes. Now I have chrome open and have the cursor in the address bar, I want to be able to press the number keys while having my app handle them but not having them show up in chromes address bar.
Thanks.
This is basically a very simplistic key logger.
EDIT)
Keyboard Hook
#endregion
using System;
using System.Text;
using System.Collections.Generic;
using System.Runtime.InteropServices;
using System.Windows.Forms;
public class GlobalKeyboardHook
{
[DllImport("user32.dll")]
static extern int CallNextHookEx(IntPtr hhk, int code, int wParam, ref keyBoardHookStruct lParam);
[DllImport("user32.dll")]
static extern IntPtr SetWindowsHookEx(int idHook, LLKeyboardHook callback, IntPtr hInstance, uint theardID);
[DllImport("user32.dll")]
static extern bool UnhookWindowsHookEx(IntPtr hInstance);
[DllImport("kernel32.dll")]
static extern IntPtr LoadLibrary(string lpFileName);
public delegate int LLKeyboardHook(int Code, int wParam, ref keyBoardHookStruct lParam);
public struct keyBoardHookStruct
{
public int vkCode;
public int scanCode;
public int flags;
public int time;
public int dwExtraInfo;
}
const int WH_KEYBOARD_LL = 13;
const int WM_KEYDOWN = 0x0100;
const int WM_KEYUP = 0x0101;
const int WM_SYSKEYDOWN = 0x0104;
const int WM_SYSKEYUP = 0x0105;
LLKeyboardHook llkh;
public List<Keys> HookedKeys = new List<Keys>();
IntPtr Hook = IntPtr.Zero;
public event KeyEventHandler KeyDown;
public event KeyEventHandler KeyUp;
public GlobalKeyboardHook()
{
llkh = new LLKeyboardHook(HookProc);
hook();
}
~GlobalKeyboardHook()
{ unhook(); }
public void hook()
{
IntPtr hInstance = LoadLibrary("User32");
Hook = SetWindowsHookEx(WH_KEYBOARD_LL, llkh, hInstance, 0);
}
public void unhook()
{
UnhookWindowsHookEx(Hook);
}
public int HookProc(int Code, int wParam, ref keyBoardHookStruct lParam)
{
if (Code >= 0)
{
Keys key = (Keys)lParam.vkCode;
if (HookedKeys.Contains(key))
{
KeyEventArgs kArg = new KeyEventArgs(key);
if ((wParam == WM_KEYDOWN || wParam == WM_SYSKEYDOWN) && (KeyDown != null))
KeyDown(this, kArg);
else if ((wParam == WM_KEYUP || wParam == WM_SYSKEYUP) && (KeyUp != null))
KeyUp(this, kArg);
if (kArg.Handled)
return 1;
}
}
return CallNextHookEx(Hook, Code, wParam, ref lParam);
}
}
Usage of GlobalKeyboardHook
GlobalKeyboardHook gHook;
private void Form1_Load(object sender, EventArgs e)
{
gHook = new GlobalKeyboardHook(); // Create a new GlobalKeyboardHook
// Declare a KeyDown Event
gHook.KeyDown += new KeyEventHandler(gHook_KeyDown);
// Add the keys you want to hook to the HookedKeys list
foreach (Keys key in Enum.GetValues(typeof(Keys)))
gHook.HookedKeys.Add(key);
}
// Handle the KeyDown Event
public void gHook_KeyDown(object sender, KeyEventArgs e)
{
textBox1.Text += ((char)e.KeyValue).ToString();
}
private void button1_Click(object sender, EventArgs e)
{
gHook.hook();
}
private void button2_Click(object sender, EventArgs e)
{
gHook.unhook();
}
private void Form1_FormClosing(object sender, FormClosingEventArgs e)
{
gHook.unhook();
}

In your hookProc, you must not call return CallNextHookEx(Hook, Code, wParam, ref lParam); if you dont want the WM_KEYS to propagate.
If you do call CallNextHookEx, the messages will be propagated.
Btw, you are aware that you are using a Global hook, and not a thread specific hook ? So you are capturing ALL key presses, and not only the ones relative to your app.